# How do you use cross products to solve (b-3)/16=5/8?

May 14, 2018

$b = 13$

#### Explanation:

Use cross-multiplication:

$\frac{b - 3}{16} = \frac{5}{8}$

$\left(b - 3\right) \times 8 = 5 \times 16$

$\left(b \times 8\right) + \left(- 3 \times 8\right) = 80$-----> opening the brackets and multiplying through

$8 b + \left(- 24\right) = 80$
$8 b - 24 = 80$

$8 b = 80 + 24$

$8 b = 104$

$b = \frac{104}{8}$

$b = 13$